“The Minnesota Twin Family Study” was performed by Thomas J. Bouchard, Matthew McGue, David T. Lykken, Auke Tellegen, and Nancy L. Segal, while the Lewis Terman performed the “Genetic Study of Genius.” In the first study, Bouchard et al. hoped to determine whether monozygotic twins reared apart had the same psychological or physiological characteristics, in terms of social attitudes, ability, interest, and tolerance, as twins reared together. In the second study, Terman hoped to find out the intelligence degree difference between the average standard, intelligent child and the gifted child.
The subjects in the Terman’s Genius Study were high IQ students from four main cities in the U.S., while the subjects in the Bouchard et al. study were monozygotic twins who were separately having been parted early in life, mainly from the U.S., the U.K. Bouchard et al. used a triangulated research approach where they did not gather all their information at once. Terman and colleagues used the Binet-Simon intelligence test, where they relied mainly on the Stanford-Binet IQ tests, the widely used test.
Bouchard et al. found that no significant differences existed between the monozygotic twin reared apart. The monozygotic twins reared together relative to personality measures like interests, hobbies, temperament, social attitudes, and career pursuits. Terman found out that high IQ subjects were socially adapted, taller, and healthier than their regular intelligent children counterparts. The significance of the data collected from the Terman study contributes to how intelligence impacts health, success, and life outcomes. The collected data from Bouchard et al.’s study helps scientists quantify modifiable and genetic environmental factors that increase certain disease risks.
The criticism leveled against the Bouchard et al. study was that the research was like a cover story or anecdotes instead of raw data. The critics believed that by bringing together any two strangers, it was possible to uncover coincidental similarities between them after a few hours. Terman’s research was criticized for lacking a generalized sample and was considered to have used an unsighted description of genetic specific preference relative to environmental explanations.
References
Bouchard, T. J., Lykken, D. T., McGue, M., Segal, N. L., & Tellegen, A. (1990). Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart. Science, 250, 4978, 223-228.
Terman, L. M. (1973). Genetic studies of genius. Stanford, Ca: Stanford University Press.